The frontrunner to become the country's next prime minister has warned of a
Greek-style social and economic meltdown if austerity measures are not
maintained.

Final rallies in Rome, Naples and Florence ahead of Sunday's general election brought a flurry of last-minute appeals to a deeply-disillusioned nation.

Polls suggest as many five million Italians have not made up their mind which party they would vote for in a country hit by a series of corporate and political scandals.

Pier Luigi Bersani, 61, the leader of the centre-Left Democratic Party and the likely next prime minister, appealed to people flirting with a protest vote to consider the stakes for the Italian economy.

Speaking to his Left-wing faithful, he warned that forescasts that up to one-fifth of voters would back Beppe Grillo, an upstart former comedian, would be a catastrophe for Italy. "The country is beset by problems and I understand people's anger, but to vote for Grillo will not get us out of trouble," Mr Bersani, the son of a mechanic, said at his party's last big set-piece rally, in Naples.

"With Grillo, who says we should leave the euro and not pay our debts, we will become worse than Greece. We must win because Europe is counting on us to win," he told 15,000 cheering supporters in the port city.

A surge in support for Mr Grillo's anti-establishment Five Star Movement has come to symbolise the uncertainty over the election outcome.

He says Italy should consider exiting the euro and defaulting on its €2 trillion debt, which at more than 120 percent of GDP is Europe's second biggest after Greece. Pollsters said Mr Grillo's political movement could win up to 20 per cent of the vote and even achieve second place by beating the centre-Right coalition of Silvio Berlusconi, the former prime minister

Mr Bersani, who started his political career as a Communist but later served as a reformist minister in a centre-Left government, also had a dig at his principal rival.

Mr Berlusconi's last government ended in ignominy in November 2011 amid a debt crisis and sex scandals involving stripping starlets and a teenage belly dancer nicknamed Ruby the Heart Stealer. "He was thinking only of Ruby, and while he was occupied with all that stuff, things went very badly for Italy," the Leftist leader said.

Mr Berlusconi's government collapsed under the pressure of the eurozone crisis, making way for a 14-month technocrat government, led by Mario Monti, a former european commissioner.

Mr Monti, who is leading a disparate group of centrists that has failed to reach expectations in polls, could still enter a coaltion led by Mr Bersani.

But the two men diverge on tax rises and labour market reforms, leaving the possibility of a deadlocked parliament that could spell disaster for Italy's economy and rattle the rest of the euro zone.

For his part, Mr Berlusconi has dismissed Mr Bersani as an unreformed Communist and plodding party hack.

In a choice put-down, the 76-year-old billionaire said: "At the very most, Bersani might be all right as the mayor of Bologna."

Many Italians agree, seeing Mr Bersani as decent but dull.

"Bersani is the most trustworthy of them all but he's lifeless," said Gabriele Brunelli as he smoked a cigarette outside his newspaper kiosk in Rome. "Grillo is just too extreme, he's always ranting. I admired Monti for the tough decisions he made as prime minister but since he threw his hat in the ring for the election he's become just another politician."

With polls putting his party in the lead with an estimated 34 per cent of the vote, Mr Bersani is likely to be the victor in the election, the result of which is expected to be known late on Monday.